The present invention relates to a conveying pipe for transportation of solids. The present invention also relates to a method of producing a conveying pipe.
The conveyance of solids, for example building materials, concrete, gravel and sand, is carried out pneumatically or hydraulically in pipelines which are assembled of multiple interconnected conveying pipes. Solids within the scope of this invention can be also materials that are present in a fluid form. For example, concrete mixtures and also sewage sludge mixtures can be considered as such.
For the coupling of the conveying pipes, they are provided with flanges or pipe collars at corresponding ends. The connection of the conveying pipes with the pipe collars is obtained either by coupling clamps or by bolts in pipe collars provided with bores.
In practice, almost all conveying pipes have pipe collars that are welded with pipe bodies. The heat effect during the welding process can however cause adverse structural changes in the conveying pipe in the connection region.
Another embodiment involves gluing of the pipe collar. DE 196 07 871 C1 discloses a conventional conveying pipe in which the pipe collars are glued to the entire outer surface of the pipe end. As a result, a heat effect is avoided by thermal joining. Practice has shown however that the service life of such glued connections repeatedly causes problems. Moreover, at high pressures or vibrations in the region of the glue joints, leaks or even sudden failure of the connection joint can occur.
In particular tolerance differences between the pipe collars and an inconsistent quality of the glue connection are causes of this.
Defective conveying pipes must be exchanged, resulting in an interruption of the conveying operation.